Targeted Substitutional Advertising (TSA) allows broadcasters/television platform operators to serve targeted advertisements to subscribers based on demographic characteristics. Within the context of a Targeted Substitutional Advertising (TSA) system, techniques may be employed to automatically derive demographic profiles of viewers and/or viewing households by monitoring attributes of the content being viewed, such as genre, time, title, channel name etc.
The following documents are believed to represent the state of the art:    Wen Jin, Anthony K. H. Tung, Jiawei Han, “Mining Top-n Local Outliers in Large Databases”, Proceedings of the Seventh ACM SIGKDD International Conference on Knowledge Discovery and Data Mining, pages 293-298, Aug. 26-29, 2001, San Francisco, Calif.;    William E. Spangler, Mordechai Gal-Or, Jerrold H. May, “Using Data Mining to Profile TV Viewers”, Communications of the ACM, volume 46 number 12, pages 66-72, December 2003;    PCT Published Patent Application WO 00/33233 of Telecom Partners Limited;    PCT Published Patent Application WO 2007/024736 of Biap Systems Inc.;    PCT Published Patent Application WO 2008/042280 of United Video Properties Inc.;    European Published Patent Application EP 0 424 648 of General Instrument Corporation; and    U.S. Pat. No. 7,260,823 to Schlack et al.